Radiative imbalance with the sky → Electrical work

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.12 × C.20 · Radiative imbalance with the sky × Photothermalfamily: PhotothermalD.12 × C.34 · Radiative imbalance with the sky × Marangonifamily: MarangoniD.12 × C.23 · Radiative imbalance with the sky × Electrokineticfamily: Electrokinetic

Typed bounds on this route

Every limit the atlas holds for this route, as constraint records: reached through bounded_by claims on the route's own entities. Hard bounds (an upper bound or a formula) decide the thermodynamic-bound check above; benchmarks, constitutive relations and resource limits are listed and never decisive. No prose limit exists anywhere (pass 42).

• Radiative cooling power bound · resource-bound · listed, never decisive
  net cooling power ≲ 100–150 W/m² under a clear sky
• Carnot limit · formula-bound · hard, applies to this route
  η ≤ 1 − T_c/T_h for any heat engine between reservoirs at T_h and T_c
• Onsager–Casimir reciprocity · constitutive-relation · listed, never decisive
  L_ij(B) = ε_i ε_j L_ji(−B): the cross-coefficients of coupled linear transport are equal up to the time-reversal parities ε of the variables and reversal of the magnetic field; L_ij = L_ji is the zero-field, even-parity case

Steps

1. 01
   Radiative imbalance with the sky —drives→ Radiative sky coolingreplicatedclaim record

   radiative → thermal

   • an emitter with high emissivity in the 8–13 µm window and high solar reflectance
   • a clear sky; humidity and cloud close the window

   refs [1] [2] [3]
2. 02
   Radiative sky cooling —produces→ Temperature gradientreplicatedclaim record

   thermal → thermal

   • the cooled surface sits a few kelvin below ambient air

   refs [1] [4] [3]
3. 03
   Temperature gradient —drives→ Marangoni effectestablishedclaim record

   thermal → kinetic · loss to thermal

   • thermocapillary case: surface tension falls with temperature, so a temperature gradient along the interface drives flow toward the cold side

   liquid · temperature gradient required

   refs [5] [6]
4. 04
   Marangoni effect —produces→ Pressure gradienttheoretically predictedclaim record

   kinetic → mechanical · loss to thermal

   • a thermocapillary-driven liquid plug moves in a closed-ended microchannel and compresses the trapped gas; the pressure rise is the load presented to the compliant membrane

   Kept below demonstrated: the Odukoya device measured heater and droplet behaviour, while the pressure field feeding the membrane (about 0.1 kPa for a 13 μm deflection in the model) comes from the force balance, not a measurement.

   refs [7] [8]
5. 05
   Pressure gradient —drives→ Streaming potentialestablishedclaim record

   mechanical → electrical · loss to thermal

   • electrolyte forced through a channel with charged walls; efficiency peaks when the Debye length is comparable to the channel width

   aqueous medium required · bulk flow required

   refs [9] [10]
6. 06
   Streaming potential —produces→ Ionic currentestablishedclaim record

   electrical → electrical

   refs [9] [10]
7. 07
   Ionic current —converts into→ Electrical workestablishedclaim record

   electrical → electrical · loss to thermal

   • electrodes exchange the ionic current for an electronic current through the external load

   refs [11]

Evidence for the complete composition · 0

No source on record for this exact composition. The sources below support the individual steps, not the route as a whole.

Evidence for the constituent relations · 11

1. [1]
   A. P. Raman et al.. Passive radiative cooling below ambient air temperature under direct sunlight (2014)

   Nature 515, 540–544 · doi:10.1038/nature13883 · crossref ✓ 2026-09-19 · record
2. [2]
   Y. Zhai et al.. Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling (2017)

   Science 355, 1062–1066 · doi:10.1126/science.aai7899 · crossref ✓ 2026-09-19 · record
3. [3]
   J.-l. Kou et al.. Daytime radiative cooling using near-black infrared emitters (2017)

   ACS Photonics 4, 626–630 · doi:10.1021/acsphotonics.6b00991 · crossref ✓ 2026-09-19 · record
4. [4]
   A. P. Raman, W. Li, S. Fan. Generating light from darkness (2019)

   Joule 3, 2679–2686 · doi:10.1016/j.joule.2019.08.009 · crossref ✓ 2026-09-19 · record
5. [5]
   L. E. Scriven, C. V. Sternling. The Marangoni Effects (1960)

   Nature 187, 186-188 · doi:10.1038/187186a0 · crossref ✓ 2026-09-20 · record
6. [6]
   Q. Dai et al.. Directional interfacial motion of liquids: Fundamentals, evaluations, and manipulation strategies (2021)

   Tribology International 154, 106749 · doi:10.1016/j.triboint.2020.106749 · crossref ✓ 2026-09-20 · record
7. [7]
   P. S. Glockner, G. F. Naterer. Surface tension and frictional resistance of thermocapillary pumping in a closed microchannel (2006)

   International Journal of Heat and Mass Transfer 49(23–24), 4424–4436 · doi:10.1016/j.ijheatmasstransfer.2006.05.005 · record
8. [8]
   A. Odukoya, G. F. Naterer. Transient response of thermocapillary pumping of a droplet in a micro heat engine (2013)

   International Journal of Heat and Mass Transfer 58, 202–212 · doi:10.1016/j.ijheatmasstransfer.2012.11.009 · record
9. [9]
   J. Yang et al.. Electrokinetic microchannel battery by means of electrokinetic and microfluidic phenomena (2003)

   Journal of Micromechanics and Microengineering 13, 963 · doi:10.1088/0960-1317/13/6/320 · crossref ✓ 2026-09-19 · record
10. [10]
    R. J. Hunter. Zeta Potential in Colloid Science: Principles and Applications (1981)

    Academic Press · doi:10.1016/C2013-0-07389-6 · crossref ✓ 2026-09-19 · record
11. [11]
    A. J. Bard, L. R. Faulkner. Electrochemical Methods: Fundamentals and Applications (2nd ed.) (2001)

    Wiley · book, no DOI · record